Field of the Invention
The present invention relates to daylight sensors for determining the ambient (i.e., total) light level in a space, and more particularly, to a daylight sensor having a rotatable enclosure for easily directing a lens of the daylight sensor towards a window.
Description of the Related Art
Many rooms in both residential and commercial buildings are illuminated by both artificial light from a lighting load, such as an incandescent lamp or a fluorescent lamp, and daylight (i.e., sunlight) shining through a window. Daylight sensors (i.e., photosensors) are often used to measure the total light level in a space in order to adjust the light intensity of the lighting load to thus adjust the total light level in the space. For example, the light intensity of the lighting load may be decreased as the daylight level increases (and vice versa), so as to maintain the total light level in the space approximately constant. A daylight sensor typically comprises a lens for directing the light in the space towards an internal photodetector (such as a photodiode) for measuring the total light level in the space. Daylight sensors are typically mounted to a ceiling in the space at a distance from the window. The lens of the daylight sensor must be positioned such that the field of view of the daylight sensor is directed towards the window. Therefore, there is a need for a daylight sensor that may easily be mounted such that the lens is directed towards a window in a space.